Conventionally, there has been known a phased-array transmitter that inputs phase-controlled transmission signals to a plurality of arranged antennas (phased-array antennas), controls directionality thereof, and outputs a transmission wave (a radiated radio wave). The phased-array transmitter, for example, is used as a transmitter of a phased-array radar or a radio communication system that performs large data transmission.
In recent years, for example, application of a phased-array radar as a FM-CW (Frequency Modulated Continuous Wave) radar has received attention. Since the FM-CW radar can accurately measure a distance to an object and a relative speed through a relatively simple configuration, the FM-CW radar has been proposed to be mounted in a vehicle to avoid a collision in advance or to perform automatic traveling in which a distance to a front vehicle is constantly maintained, for example.
For example, a phased-array transmitter (a transceiver) used in the FM-CW radar is provided with a BIST (Built-In Self Test) circuit that performs self-test (self-diagnosis) that a transmission signal is normal.
The BIST circuit, for example, is used in order to perform the reduction of a test process at the time of manufacturing of a semiconductor chip in which the phased-array transmitter has been formed or at the time of assembling of a FM-CW radar apparatus, or to perform abnormality detection and operation compensation (amplitude/phase control) at the time of a product operation.
At the time of the product operation, for example, at the time of power-up of the FM-CW radar apparatus provided with the phased-array transmitter or at the time of a rapid change and the like in environmental temperature in which the FM-CW radar apparatus is used, a self-test is performed to control the directional characteristics of a radiated radio wave.
As described above, for example, the FM-CW radar apparatus provided with the BIST circuit has been proposed; however, for example, a PLL (Phase locked Loop) for transmission and a PLL for BIST are configured to be controlled by dedicated digital circuits, respectively.
When the respective digital circuits are provided to the PLL (PLL-TX) for transmission and a PLL (PLL for BIST: PLL-BIST) for self-test, it causes an increase in power consumption and an occupation area. Moreover, since it takes a time to set the PLL-TX and the PLL-BIST, it takes a long time to perform processes using the BIST circuit.
Incidentally, in the past, various phased-array transmitters, transceivers, or radar apparatuses have been proposed.
Patent Document 1: Japanese Laid-open Patent Publication No. H01-227977
Patent Document 2: Japanese Laid-open Utility Model Publication No. H10-186025
Patent Document 3: Japanese Laid-open Patent Publication No. H05-264728